Which agent is the best choice for intraoperative control of hypertension?

The best choice for intraoperative control of hypertension is hydralazine. This agent is a direct vasodilator that works by relaxing the smooth muscles in the arterial walls, leading to a decrease in vascular resistance and lowering blood pressure. It is particularly effective in scenarios that require rapid control of blood pressure, such as during surgery when patients may experience sudden spikes in hypertension due to stress or the effects of anesthesia.

While labetalol is also an effective agent for managing hypertension during surgery due to its mixed alpha and beta-blocking properties, it is typically utilized for cases requiring both heart rate and blood pressure control. Propranolol, on the other hand, is primarily a non-selective beta-blocker used for managing heart rate and doesn't directly address acute hypertension in the same manner. Opioids, while effective for pain management, do not have a primary role in controlling blood pressure and may not be reliable for this purpose.

Therefore, hydralazine stands out as the most suitable option when immediate blood pressure reduction is necessary during surgical procedures.